In 2015, the United States Federal Highway Administration (FHWA) requested $51.3 billion “to maintain and improve the safety, condition, and performance of our national highway system, and enable FHWA to provide effective stewardship and oversight of highway programs and funding” for the 2016 fiscal year (FHWA, 2015). This value is minimal compared to the estimated $76 billion needed to repair or replace the roughly 65,000 structurally deficient bridges in the country (ASCE, 2013). In addition to bridge repair, FHWA funds are needed for road maintenance, traffic monitoring and safety, inspections, new design, and new construction along with a long list of logistical costs. Due to financial constraints, there is a major push for new, innovative solutions to reduce design, construction, maintenance, repair, and logistical costs for infrastructure projects. Incorporating technological advances into current design practices is one avenue that is being explored and has promise to be extremely beneficial.
The development of “smart” bridge bearing technology has the potential to solve many problems that the FHWA, state Departments of Transportation (DOTs), and private bridge owners are facing. Bridge bearings are structural components that are designed to allow translation and rotation of a bridge. They support the superstructure of a bridge and transfer loads from the superstructure to the substructure. There are several types of bearings including, for example, rocker, spherical, elastomeric, sliding, and pot bearings.
Based on the current state of the art, bridge bearings are monitored by visual inspection. Bridge weigh-in-motion studies are conducted on a case by case basis where the bridge is instrumented and monitored for a given period of time. This process is expensive, time consuming, and still has several uncertainties when analyzing the results. Traffic statistics are usually collected manually or with traffic counters laid across roadways. Inspections and design validations are conducted by updating the as-built design with the existing conditions of the bridge and determining its response to design loads. Therefore, an improved and cost-efficient “smart” bridge bearing may be desirable.